Corrugated paper board container having sealed fluted closure flaps

ABSTRACT

Method and apparatus is disclosed for protecting a corrugated paperboard product from the deteriorating effects of high humidity or extreme dust conditions, wherein the exposed fluted edges of the corrugated paperboard stock are cut, crushed and coated with a barrier material to seal the exposed flutes thereby preventing the impregnation of water or dust into the interior of the corrugated paperboard stock.

United States Patent Wagner 1 51 Jan. 18, 1972 [541 CORRUGATED PAPER BOARD 916,544 3/1909 Ferres ..229/D1G. 2 CONTAINER HAVING SEALED FLUTED 3,348,756 10/1967 Boysen ..229/37 3,186,896 Clem ..229/3.5 X

App]. No.: 825,375

U.S. Cl. ..229/37 R, 117/158, 161/43,

161/44, 161/149, 229/3.1, 229/35 R, 229/DIG. 2 Int. Cl. ..B65d 5/02, B65d 25/14 Field 01 Search ..229/3.5, 37, 44, 14, DIG. 2,

References Cited UNITED STATES PATENTS Guesdal ..117/158 X Primary Examiner-Joseph R. Leclair Assistant Examiner-Steven E. Lipman Attorney-Larry C. Hall and Robert S.. Grimshaw [57] ABSTRACT 1 Claims, 12 Drawing Figures PAIETEB JAN 8 1m 3 6 350 5 1 sum 1 0F 3 INVENTOR Fmn/r/fn J. Wagner BY I ATTORNEY PATENTEU JAN18|972 SHEET 2 BF 3 ZNVENTOR Fmn/r/m J Wagner ATTORNEY CORRUGATED PAPER BOARD CONTAINER HAVING SEALED FLUTEI) CLOSURE FLAPS BRIEF DESCRIPTION OF INVENTION This invention relates generally to both the method and apparatus for producing a corrugated paperboard product with special application to use under severe moisture conditions. The invention relates more particularly to containers or other corrugated paperboard products which might be subjected to storage and/or other use under conditions of hydrocooling or high humidity. Moreover, the invention finds application in the protection against infestation by vermin or other undesirable matter such as dust which could produce a contamination or destruction of the corrugated paperboard product.

The products made using the teachings of this invention would find a wide application of use, but are particularly useful in the packaging of commodities for shipment and storage which require hydrocooling, top icing, outdoor storage and all other cases where moisture might be encountered. In particular a shipping container treated by the process of this invention would provide an excellent thermal barrier for the commodity stored therein. The container so treated would not only be protected against moisture penetration, but would be resistant to infestation by other deteriorating foreign matter thereby adding to the strength and integrity of the container itself.

The invention as practiced on the container set forth about would comprise taking the corrugated paperboard stock,

either in roll or blank form, from which the container would,

be constructed, and sealing the exposed fluted edges of the corrugated board. Specifically, the invention would require that the blank be operated on by the method steps hereinafter explained, either by the herein-described apparatus or other substantially similar apparatus, to initially cut the fluted edges of the blank along an angle other than ninety degrees so as to expose an area of the fluted corrugated medium which would be greater than that area exposed by a normal, or ninety 7 degree cut; secondly, this cut or skiived edge would then be crushed by passing the corrugated blank between cooperating male and female crushing rolls or disks so as to partially close or seal the previously exposed flutes; thirdly, the entire blank would be coated either on one or both sides with a moisture impervious coating while layingdown a thicker bead of coating along previously cut and crushed fluted edges. Accordingly, this process would effectively and economically seal the normally exposed fluted edge of a corrugated paperboard stock material against the entry by way of the open flutes of any foreign material such as water, moisture-laden air currents, vermin or dust which might cause delaminating of the corrugated board itself.

Different attempts by others to accomplish the results obtained by the above-described process have either proven unsatisfactory, insufl'rcient or too expensive for ordinary production techniques in the highly competitive low-return industry of corrugated paperboard manufacture. At least one approach comprised the cumbersome and ineffective practice of extending and folding one of the corrugated board liners over the other, then gluing the two liners together to seal the flutes. This practice obviously could not have solved the moisture penetration problem as effectively as the present invention and as simply as the present invention.

Of course, other and different solutions to the edge seal problem have been suggested including taped and glued edges and wax or plastic-spraying techniques to force the water-impervious material into the flutes. However, these different approaches have not been successful to the same extent that the present solution has as practiced in accordance with the dis closed invention.

In tests performed on corrugated containers with open flutes, taped flutes, an angle cut with regular curtain coating and an angle cut with bead curtain coating, the following results were obtained.

COMPRESSION TEST 2 Min. 10 Min. Standard Water Water Sample Condition Sonlt Shower Open Flutes 1405 647% [MS-64% Taped Flutes 1468 648-441: l043-7l% Angle Cut-Crushed Regular Curtain Costing 1480 647% IMO-68% Angle Cut-Crushed Bead Curtain Coating IMO "52-82% lass-97% The Standard Condition represents the load applied in compression to destruct the container when dry. The numbers in the columns Z-Minute Water Soak" and IO-Minute Water Shower, represent the load applied in compression to destruct the container 30 minutes after the test with the percentages representing a percentage of the original dry strength.

The results do shown an advantage, both in soaking and under the shower, of the bead coated cut edge as opposed to the taped flutes. The anglecut and bead-curtain coated container retained 82 percent an 97 percent of its initial compression strength in the soak and shower test respectively. When the fluted edge was angle-cut and the container blank simply curtain coated in the normal manner, the resultant container performed about the same if not worse than the normal open flutes. The answer to this performance is obvious, however, when one recognizes that by angle-cutting the flutes a greater area of the flute is exposed to the elements than would-be exposed by a normal cut. v

The container with taped flutes did not perform satisfactorily in either test partly because the tape had a tendency to peel and delaminate from the edge of the board upon contact with the water.

It could further be deduced that an edge crush alone, or, an edge spray by itself would not give satisfactory results in a similar test. The edge crush alone would have a tendency to separate as the tape did, and the imperfections attendant with an edge spray by itself would leave voids where water would still have a tendency to penetrate.

Of course it should be pointed out that this invention would be applied preferably of those containers destined for use where the container would normally be curtain coated or otherwise coated with a film of water" impervious material. Hence, an extremely important advantage of this invention is one whereby the heavy bead of coating; material is applied to effectively seal the flutes at the same time that the normal faces of the container blank are coated. This feature along with the previously anglecut fluted edge (to expose a greater area of the flutes for better sealing), and the unique crushing step (which would in itself serve to inhibit water penetration), comprise the novelty of the inventive concept herein disclosed and claimed.

Accordingly, with these objects in view, the novel features of the invention and the method of carrying it out will more fully appear from the following detailed description when read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not intended as a definition of the limits of the invention, reference being made primarily for this latter purpose to the appended claims.

BRIEF DESCRIPTION OF DRAWING FIG. 1 illustrates a schematic representation of the apparatus used for carrying out the novel features of the invention;

FIG. 2a shows in perspective a typical corrugated board blank, or piece of stock, with normal side-fluted edges;

FIG. 2b shows the same corrugated blank of FIG. 2a after having been passed through the angle edge-cutting stage of the preferred apparatus of FIG. 1;

FIG. 20 shows an end view of the corrugated blank of FIG. 2b;

FIG. 2d shows an end view of a corrugated blank after being angle-cut with a modified angle-cutting stage;

FIG. 3 shows schematically an end view of the edge-crushing disks or rolls used in the FIG. 1 apparatus;

FIG. 4a shows an end view of the corrugated paperboard blank of FIG. 2b after having been passed through the edgecrushing stage of the preferred apparatus of FIG. 1;

FIG. 4b shows a perspective view of the corrugated blank of FIG. 4a;

FIG. 5 shows schematically how corrugated paperboard taken from the corrugator might be operated on to carry out the preferred features of this invention;

FIG. 6 shows a typical blank which could be treated with the steps of this invention;

FIG. 7 shown the container constructed from the blank of FIG. 6 erected and prior to being closed; and,

FIG. 8 shows the container of FIG. 7 closed and ready for shipment.

DETAILED DESCRIPTION Preliminary to consideration of a detailed description of the various elements of this invention, it should be noted that:

several factors of major importance in the production of containers, namely, economics, performance and ease of integration into existing machinery, were primary considerations in the development of the invention. Also, in view of the fact that the invention is directed to the control or penetration of moisture, vapor, grease or other foreign matter such as dust, into the raw or exposed edges of the paperboard material, it was essential to the effective practice of the invention that the sheet stock from which the carton blanks are formed, or, the blanks themselves-be provided with a moisture, vapor and/or grease-repellent layer on either one or both sides. More specifically, for the practice of the present invention it was found most desirable to use the curtain-container technique to apply the preferably wax moistureproof layer. Thus, because the container blank has to be coated, and because an important step in the functioning ofthe invention was to be carried out on the curtain coater itself, the economics of the final product were readily enhanced. Furthermore, the ability to integrate the various steps of the invention into presently used apparatus must be appreciated. The addition of the angle edge-cutting mechanism andedge-crushing devices were also readily accomplished with a minimum amount of redesign and effort to further point out the economies of the present invention as compared with the prior art devices.

The perfonnance of the containers so constructed is mar kedly better than the prior art containers especially when subjected to hydrocooling. Hydrocooling is, of course, the practice of spraying directly with water the container and its comniodity to maintain a freshness not approached by other forms of cooling.

Accordingly, the method of the invention as preferably practiced is shown schematically in the apparatus of FIG. 1, wherein station 10 is illustrated as a blank supply and feeder mechanism. It should be appreciated at the outset, however, that the illustrated blank-feeding device could in fact be a supply of corrugated paperboard or the like in roll form as shown in FIG. 5, for use in a pallet, or cornerpost, or any other paperboard product. For the sake of convenience and illustration, however, a blank for making a hydrocooled container has been chosen. FIG. 1 further shows in sequence an edgecutting station 20, an edge-crushing station 30, a first curtaincoating station 40, a blank turnover mechanism 50 and a second curtain-coating station 40'.

The blank feeder includes a pair of guide members 12 mounted on a pair of structural side'rails l4 'on which the blank travels as it proceeds through the different manufacturing steps of the invention. A supply of corrugated paperboard blanks 11 are shown which become activated by the feeder fingers 13. Each of these different elements are of conventional design which would be adapted for the desired installation.

Blanks are slipped from the bottom of the supply stack 11 onto the side rails 14 and are moved along the side rails by a conventional feeding mechanism, for example, a dog-type feed (not shown). The blanks 11 may be formed from plain untreated kraft paper or may be partially pretreated depending upon the ultimate use to which the finished container is to be put. For instance, it has been found that for very severe moisture conditions, specifically hydrocooling, it is desirable to use a pretreated blank wherein either the liners or the corrugated medium or both have been impregnated with a moisture-resistant material. Blanks made from wax-impregnated board constructed with a water-resistant adhesive have proven completely satisfactory under the most severe conditions. Such board has been generally coated with a hot melt blend to provide high resistance to moisture, water vapor, oils and gases. The coating gives a durable packaging surface which prevents wear and protects against many abuses to which a container is exposed. The coating also provides an attractive, high-quality gloss surface over printing and graphics to enhance the appearance of the container while providing a skid-resistant feature to increase stability in stacking, handling and pelletizing.

The blanks 15 so treated are moved along the machine rails 14 so that an edge portion 16 is passed through a slot 23 in the edge-cutting head 22 at station 20. The edge-cutting station 20 is shown as having a cutting head 22 at each side of the blank mounted on a stanchion or the like 21. Any desirable means for mounting the cutting head 22 may be employed as long as it is placed in the general proximity of the edge of the blank 15. Of course the blank must have been prearranged so that the flutes of the corrugated board are positioned transverse to the direction of movement. In this way the fluted edges of the blank are presented to the cutting head which performs the angle cut in a manner hereinafter described.

The cutting heads 22 each comprise a base member wherein there is located an industrial type, fixed razor blade mounted at an angle of other than with regard to the plane of the blank. It has been found that a blade angle of approximately 45 works most satisfactorily. In addition means are preferably provided to reposition the razor blade at designated time intervals to thereby present a different portion of the blade to the incoming blank and distribute the wear along the blade. None of these features have been specifically illustrated since they are deemed to be collateral to the inventive concept herein and subject to being carried out in various difierent ways. For instance, a pair of rotary blades could be used in the two cutting heads if desired as opposed to the fixed blades herein proposed.

Careful attention to FIG. 1 will illustrate that the portion of the blank 15 which has progressed through the'cutting head 22 has an edge configuration 16 which is different from that portion of the blank which has not entered the cutting head. FIGS. 2a and 2b also illustrate the edge configuration 16 before and after the angular edge cutting operation. Further and more detailed attention to FIG. 1 and to FIG. 20 will illustrate a feature of the invention which is characteristic of the specific embodiment disclosed-although not a binding requirement of the inventive concept.

As noted in both FIG. 2c and in FIG. 1, the cuts on each side of the blank 15 leave an edge shape 16 which is similar, i.e., with the same angular relationship thereby leaving the face of the cut on one side of blank 15 up while leaving the face of the cut on the other side of the blank down. This distinction has been made herein for a purpose to be latter described in conjunction with the presence of the turnover mechanism 50 included in FIG. 1 apparatus. Suffice it to point out that the cut need not take the same angular configuration but may take the form shown in the edge view of FIG. 2d. In this FIGURE the two blades would be mounted at the same angle but in converging or intersecting rather than parallel planes so that the angular cut at each side the blank I5 would have its exposed edge face to up.

As a matter of practicality and specifically for the theoretical installation shown in FIG. 1, the blades in each cutting head 22 would be mounted at 45 and pointed in the same direction to lie in parallel planes spaced apart a distance equal to the width of the blank I5. This configuration would yield edge cuts to like those shown in FIG. 2c wherein the cut faces would be reversed. This orientation would be useful where both sides of the blank were to be coated so that when the blank was passed through the curtain coater one of the cut faces would be up and a single bead in the curtain would be sufficient to seal the flutes of that cut upper face. Similarly when the other side of the blank was to be coated, the blank would be passed through either the same or a different curtain coated and the down cut face on the first pass would be the up cut fact on the second pass. Accordingly either the same single curtain bead or a properly oriented curtain bead in a different curtain coater would effectively seal the flutes of the second cut face.

Where only one side of the blank I5 needed coating, a blank form as shown in FIG. 2d would be used with the curtain coater containing two beads, one at each side of the blank, in order to apply an extra, sealing portion of wax at each exposed cut face. Naturally the blades in each cutting head 22 would be angularly disposed but divergent for this blank form as hereinbefore set forth. In addition, in some instances, where only a single fluted edge was required to be cut, the blade in one of the cutting heads could be removed, or the entire head could be moved away from the blank so as to out only one side of the blank.

After passing through the cutting station 20, the blank is then conveyed to the edge-crushing station 3b. In the form illustrated, the edge crushers 30 at each side of the blank consist of a pair of upper grooved disks or rolls 32 and a complementary pair of lower grooved disks or rolls 34. Each crushing element is suitable supported by a stanchion member Ell, 33 and the crushing elements are positioned relative to one another so as to allow the blank to pass between them, but to substantially close the previously cut fluted edges of the blank. This relative relationship is shown more particularly in FIG. 3.

Particular attention to FIG. I clearly shows the difference between the blank edge 16 before and after passing through the edge-crushing stage 30. At this point in the blank manufacture, two of the steps in production have been finished and the blank at this time has its fluted edges partially sealed against moisture penetration. The particular design of the crushing wheels 32, PM is only of relative importance as long as certain criteria is carried out. The illustration of FIG. 3 shows the outer surface of each crushing element as being grooved or at least substantially uneven, but complementary with its adjacent element. The primary concern with the shape of the crushing elements is only that they be designed to close the flutes but not otherwise damage or weaken the board. The secondary concern with the edge-crushing station is that the female and male portions of the edge-crushing elements be properly oriented to carry out the desired results.

In the FIG. I embodiment, where the knife blades of edge cutters 22 are parallel to produce an upper cut face In at one side of the blank, and a lower cut face 16 at the other side of the blank, the edge-crushing wheels must be reversed at each side of the blank in order that the female element of each pair will be in contact with the back side of the cut face. In this manner, the male element of each pair will be able to engage and completely seal the exposed flutes on the face of the cut. Where a blank in the form of FIG. 2d is to be produced, the edge-crushing elements would have the identical orientation at each side of the blank I5.

Notwithstanding the illustration of a complete assembly line operation in FIG. I, the edges of the blank or other form of corrugated paperboard material could be cut at an angle and crushed to partially seal using different methods. The cutting and crushing for the above operation could be accomplished at the corrugator, or at a slitter, or in a special machine designed and built for the specific purpose. It could be accomplished on a die press by sawing with the knife inserted at the proper angle and by crushing using hard rubber around the edge of the knife blade. The construction of a die press is such that the diecutting elements, or knives are surrounded by soft rubber so that when a blank is to be cut, the cut is made without damaging the material adjacent the cut. With the modified die press cited above, the cut would still be made, but, the hard rubber adjacent the knife would serve to crush the exposed flutes substantially as done by the edge crushing elements herein disclosed.

Subsequent to passing through the edge crushing station 30, the blanks would then be ready for their curtain coating and edge sealing operation. In the FIG. I embodiment a pair of curtain coaters dtl and 40' are installed in-line, and separated from one another by a blank turnover mechanism. This installation is useful, of course, where the blank is to be coated both sides. If the blank of FIG. 2c was being manufactured, the first curtain coater installation dd would be modified to present a heavier bead of coating along the upper, exposed flutes of blank formed in the angle-cut face to. Similarly, the second curtain coater 40' would be modified to present a heavier head of coating to the exposed flutes on the other side of blank 15 after it was turned over. If the blank of FIG. 2d was being manufactured, only one of the curtain coaters would need modification to present a heavier bead of coating at each side of the blank for simultaneously coating the exposed flutes formed in each of the upper cut faces I6 of blank 15 at each side thereof. The other curtain coater would operate conventionally to simply coat the second side of the blank after passing through the turnover device.

The two curtain coaters illustrated may take any particular form as provided by the four major manufacturers of curtain coaters in the United States. These manufacturers make the Egan coater, the Steinemann coater marketed as Ashdee- Steinemann, the Equi-Flow coater and the Gasway coater. In each of these coaters, there are many distinctions and characteristics either in design or operation. However, there are only two main elements to any curtain-coating system, namely, a means for creating a curtain wall of coating material and a conveyor system to transport the material to be coated through this curtain. There are several means whereby the curtain is effected and these vary in accordance with the specific equipment types. In the Steinemann system, a V- shaped head, consisting of two metal plates is used. At the base of the V," a small space permits the flow of molten material pumped under pressure to this head. The two metal plates forming the V are adjustable so that the extruded material or curtain can be varied in thickness. In the Gasway process, material under pressure is pumped into a trough. The trough overflows and the liquid flows over the edge of a steel plate, called a weir, and down its side. This weir forms the curtain.

When the curtain is not falling on the surface of the material to be coated, it flows into a spill trough and from thence into a recirculating tank where it is pumped back up to the curtain head for reuse. These elements are shown schematically in FIG. 1 wherein the numeral d1 indicates the spill trough with means (not shown) for conducting the excess coating material back to the curtain head for reuse, Consequently, curtain coating is an extremely economical process, since material not actually applied to the surface of the substrate can be reused. The amount of the coating being applied, in any given application, is determined by the thickness of the curtain and the speed of the substrate as it passes through the curtain.

For the purposes of this invention, and, in order to produce a bead of coating material of increased thickness along the cut and crushed face of the fluted edge, some means was required to be inserted into the curtain to create an increased flow at a 7 selected location. To carryout this requirement at small trough-shaped device in the shape of a V" and closed at one end, was inserted into the curtain flow. This device served to collect a portion of the curtain 42 and allow the collected part to flow out the open end of the V" in a thick bead 45. The device was, of course, positioned so that the thickened bead coincided with the face of the cut and crushed fluted edge. However, this is not deemed to be the only means for accomplishing this purpose since just about anything that is placed in the curtain tends to cause it to become thickened at that point.

The turnover mechanism 50 illustrated in FIG. 1 may take any desirable form in order to accomplish the result, this mechanism only being necessary for in-line operations where it is necessary to coat both sides of the blank.

FIG. shows schematically how corrugated paperboard taken directly from the end of a corrugating machine could be operated to carry out the steps of this invention. In the drawing, a roll of corrugated paperboard 60, which may be as wide as the corrugator itself, is unwound by any suitable means and passed through a slitting station 61 which could include any number of slitting blades 62, 63 mounted on a slitter bar 66. The number of slitting blades would correspond to the desired width of paperboard needed for use in blank form. The slitting station is of a conventional form whereby the bar 66 has it ends mounted in standards 64, 65 at each side of the web to cooperate with a base member 67.

Slitter blades 62, 63, as shown, cut the web W into three smaller webs 72, 73 and 74 which are then operated on by apparatus similar to that used in the FIG. 1 embodiment, to cut and crush the fluted edges in accordance with the present inventive concept. For this purpose, a plurality of edge cutting stations 68, 69, 70 and 71 are incorporated adjacent the plurality of fluted edges created by the slitters at 62, 63. The edge-cutting heads 68 and 71 each include a blade or other cutting device mounted at 45 to the plane of the paperboard so as to cut the fluted edge and expose the open flutes prior to being crushed. The cutting heads 69 and 70. each include a pair of cutting devices mountedat the prescribed 45 angle to operate on the adjacent edges of webs 72, 73 and 73, 74 respectively. For this purpose, and as hereinbefore set forth, the blades or cutting devices of heads 69 and 70 could be spaced apart and parallel to one another, or, spaced apart and in converging planes with respect to one another. The orientation of the two cutting devices would be dictated by the type of cut desired at each side of the web as illustrated in FIGS. and 2d.

Of course, when desired, it would be possible to cut only a single fluted edge of the web. This same technique could also be applied to the corrugated paperboard in blank form as stated hereinbefore, and would be done where it was only necessary to seal the flutes at one edge of the board. A situation requiring sealed flutes at one end only would arise where the containers formed from the paperboard were to be stacked on top of one another, or where a top closure element overlapping the upper edge of the container was to be used. In these example circumstances a cut and crushed upper edge would tend to cut into the adjacent container or top thereby weakening the material.

After the fluted edges are cut, the webs 72, 73, 74 are each passed through the edgecrushing devices 75, 76, 77 and 78. The illustration in FIG. 5 shows each crushing wheel mounted on a bar 79 which is in turn mounted between standards 81, 82. Only a single mating wheel 80 is shown to cooperate with the wheel 75, however, it is to be understood that each crushing wheel would have a cooperating lower wheel to substantially close the previously exposed flutes. Crushing wheels 75 and 78 would be designed to have a configuration for crushing only a single cut edge whereas wheels 76 and 77 would have the capability of crushing the two adjacent edges of webs 72, 73 and 73, 74 respectively. Alternatively, and if the adjacent edges of the multiple webs were substantially separated from one another, pairs of crushing wheels would have to be used in the intermediate positions to effectively and substantially seal the exposed flutes.

From this stage of the operation the three webs 72, 73 and 74 are passed over turning bars 83 and 84 to be rewound on separate rolls indicated at 85, 86 and 87. With the corrugated paperboard thus treated, it would then be usable for making blanks to be formed into containers or the like. It should be noted however, that at this stage of the treatment as depicted in FIG. 5, the board has not yet been printed or coated as would normally be done for the containersof this invention. For the purposes of this invention, the corrugated paperboard when treated as shown in the FIG. 5 illustration, would subsequently be cut into blanks for forming a product. The blanks would then be passed through a die press or printer slotter where they would be printed and cut to assume their final configuration.

An example of one form of container blank which was made using the inventive process is shown in FIG. 6. The blank configuration shown'therein comprised a trial order for the shipment of a commodity under hydrocooled conditions. The details of construction of the blank itself are not a part of this invention but are described herein only for the sake of clarity.

A plurality of wall panels -104 are connected to one another by parallel fold lines with identical bottom and top closure flaps 104-110 attached at each end of the wall panels. The closure means at both the bottom and the top are identical in this case because of the nature of the product for which the container was designed. As noted in FIGS. 7 and 8, the top closure flaps do not meet in the center since a complete closure was not necessary. The closure flaps 106 and 109 are adapted to be inserted into the slots formed by the tabs 111 to hold both the bottom and the top in place.

Since the container blank was designed for hydrocooling, it was deemed desirable to keep the blank as nearly rectangular as possible. In this manner the entire fluted edges 16 were treated with one pass through the cutting and crushing heads leaving no unevenly cut exposed flutes. For the actual case, the blanks 15 were initially cut and crushed as shown in FIG; 1. The blank was then printed, scored and cut to provide the graphics, the score lines for folding and the hand holes and tabs 111, and, finally it was curtain-coated while applying a bead of coating on the fluted edges at 16. The container thus formed satisfied the customers needs and proved to be successful in transporting the goods under severe moisture conditrons.

There is thus provided "a novel apparatus and method for producing a novel product, namely an edge-sealed container for use under severe moisture conditions. The apparatus and method so described and illustrated are not deemed to be limiting, however, since it is to be expressly understood that various changes may be made therein, particularly in the design and arrangement of the parts and in the materials specified, without departing from the spirit and scope of the invention, as will now be understood by those skilled in the I claim:

1. A container constructed from corrugated paperboard and protected against the deteriorating effects of high humidity and against the penetration of foreign matter, comprising:

a. primary sidewalls having upper and lower closure flaps hingedly attached thereto, said closure flaps having their fluted edges exposed to the weather;

b. said upper and lower closure flaps having only their fluted edges cut along an angle to exp se an oblique planar surface of fluted corrugated medium;

c. said upper and lower closure flaps having only their cut fluted edges crushed to a closed condition to prevent the entry therein of foreign matter; and,

d. said container primary side walls and closure flaps being completely surface coated with a moistureproof barrier coating while said upper and lower closure flap edges are further simultaneously sealed with a bead of moistureproof coating of increased thickness only in the region of said cut and crushed fluted edges.

4 i l II I 

1. A container constructed from corrugated paperboard and protected against the deteriorating effects of high humidity and against the penetration of foreign matter, comprising: a. primary sidewalls having upper and lower closure flaps hingedly attached thereto, said closure flaps having their fluted edges exposed to the weather; b. said upper and lower closure flaps having only their fluted edges cut along an angle to expose an oblique planar surface of fluted corrugated medium; c. said upper and lower closure flaps having only their cut fluted edges crushed to a closed condition to prevent the entry therein of foreign matter; and, d. said container primary side walls and closure flaps being completely surface coated with a moistureproof barrier coating while said upper and lower closure flap edges are further simultaneously sealed with a bead of moistureproof coating of increased thickness only in the region of said cut and crushed fluted edges. 